Thermostatic device.



- No. 66l,73|. Patented Nov. l3, I900.

R. G. CALLUM.

THERMOSTATIG DEVICE.

(Application filed Dec. 80, 1899.)

(No Model.)

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UNITED STATES PATENT @FFICE ROBERT G. OALLUM, OF WASHINGTON, DISTRICT OF COLUMBIA.

THERMOSTATEC DEVICE.

SPECIFICATION forming part of Letters Patent No. 661,781, dated November 13, 1900.

Application filed December 30, i899. Serial No. M2085. lNo model-J To all w/wm it 71mg conceive;

Be it known that I, ROBERT G. OALLUM, a citizen ofthe United States, residing at \Vashington, District of Columbia, have invented certain new and useful Improvements in Thermostatic Devices; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawing, and to the letters of reference marked thereon, which forms a part of this specification.

This invention is directed to improvements in the class of thermostats which are designed for use more especially in connection with fire-alarm and other like systems, the object of the invention being the production of a thermostatic device constructed to be thoroughly reliable in action even under extraordinary usage.

The nature of the invention will be readily understood by reference to the following detailed description and to the accompanying drawing, in which is illustrated a thermostatic device embodying the invention.

Referring to the drawing by letter, A denotes the base-plate, which is constructed of non-conducting material, such as porcelain, and which is provided with apertured ears a, through which are passed securing-screws in the usual manner. To the outer or face side of the base-plate is secured a supportingplate 5, to which is attached, by means of screws 0 c, a bracket-arm 01, having its outer end extending lateral-1y beyond the supporting-plate and provided with lower projections d and an upper projection d through which is passed a screw CF. The projections d are bent upwardly at an angle to provide jaws and serve with the screw d to clamp the thermostat E and support it free of the plate 1) and base-plate. The thermostat E is of approximately circular form and is clamped near one of its ends, whereby the other end is permitted a comparatively wide range of movement. On the free end of the thermostat is adjustably secured an arm f, carrying a pin f. This arm, which forms an extension of the thermostat, is provided with a slotf through which is passed a screwf the latter entering an ear 6, extending outwardly from the thermostat, whereby the adjustment of the arm to lengthen or shorten the thermostat is readily effected. Secured to the plate Z) is a block G of vulcanized rubber, fiber, or otherinsulating material. Slots g are provided in the block to receive contacts h, h, and 7L2, which contacts are of flexible sheet metal and are bent to one side of the slots and secured by means of screws g, 9 and g Wires i, i, and 2' lead, respectively, from the contacts it, h, and 7L2 to binding-screws on the base-plate and from thence to the circuit. The contact h is interposed between the contacts 7L and h and is extended across the path of the pin f, carried by the thermostat. The contacts h and 7L2 are bent at their free ends inwardly, and contact is normally maintained between the contacts h and W, whereby there is provided a normallyclosed circuit, in which may be placed a suitable device controlled by the circuit to indicate both the presence and absence of current, the purpose being to insure notice of a broken circuit occurring through accident or tampering with the thermostatic device and its connections. The extension of the thermostat is preferably so adjusted that a slight range of movement of the thermostat is permitted before the pin f engages the contact h, so that under normal conditions any vibrations of the thermostat occasioned by jar are not communicated to the contacts and no false signals result. Then by the employment of the adjustable extension the device may be set to operate at different temperatures. In the operation of the device when the temperature shall have reached a predetermined degree-say 1l0-the movement of the expanding thermostat will have been sufficient to have carried the pin against the contact 7L and forced it away from the contact 7L2. The separation of these contacts results in the circuit becoming broken, and consequently the exhibition, by means of an indicator, annunciator, or the like, of the fact that the heat has reached the danger-point. Should the temperature continue to rise, further expansion of the thermostat will cause the contact It to be carried against the contact 7b, with the result of closing a circuit in which is a fire-alarm signal giving notice of the existence of a fire temperature in the place of location of the device. The device is therefore designed to signal an interrupted current due to disarrangement of the parts or the breakage of the wires, to indicate when the heat has reached the danger-point, and to sound an alarm when the temperature rises above said point.

The device is very simple in construction, and hence is not liable to disorder, and the employment of the resilient contacts insures good electrical contact for the transmission of the current. The form of the thermostat renders it very sensitive to the changes in temperature and permits it to have a comparatively wide range of movement. The device is preferably provided with a cap or cover, which being of the usual construction is not here shown.

I claim as my invention-- l. A thermostatic device having a thermof stat provided with an adjustable extension carrying a shoulder, two contacts, and a third contact between them the free end of which is in the path of the shoulder.

2. A thermostatic device having a thermostat of circular form supported near one end and having at its free end an adjustable extension carrying a pin, a block, a contact having one end in the block and its other end in the path of the pin, and a contact at each side of the aforesaid contact.

In testimony whereof I aflix my signature in presence of two witnesses.

ROBERT G. CALLUM.

Vt itnesses:

WILLIAM HEINE, W. TAYLOR. 

